抄録
In order to obtain the fundamental information on the thermal performance of a semi-underground house, calculations based on the two-dimensional finite element method were made for various forms of underground thermal insulations, as well as long-term field measurements using a twin-type test house. This paper describes the calculation results yielded by a series of parametric computer simulations using standard weather data of city of Sendai. Before a series of calculations, test calculations were made and it was confirmed that the calculated room temperature fluctuations approximately agree with measured fluctuations in the two test rooms. After the test calculations, the effect of the following factors on the room temperature fluctuation and on the heating and cooling loads was computed using room models whose size and building materials were similar to that of the test house: (1) Forms of thermal insulation around the underground walls (2) Solar incident through the windows and use of night insulation (3) Air conditioning mode (4) Thermal characteristics of soil around the construction In addition, the thermal performance of the semi-underground room was compared with other types of rooms (slab-on-grade type and basement type). Main results obtained by calculations are shown as follows: (1) There was little difference between the yearly mean temperatures for various forms of insulation. However, the difference between the maximum and minimum monthly mean room temperature was widely distributed between 8℃ and 16℃. The difference for the group of cases with horizontal insulation was smallest. (2) The heating and cooling loads of semi-underground rooms with various forms of insulation were about 0.5 times as large as that of the slab-on-grade room. (3) Under the situation of controlled room temperature between 18℃ and 26℃, the cooling loads in the case with insulation on the whole interior surface was highest in all cases of insulation formations. However, the cooling loads except this case were very low and there might be no need for any auxiliary cooling systems.
